Little Boys' 

US Sizes Chest (in) Waist (in) Hips (in) Height (in)
4 21.5 - 22.5 21.5-22.5 22.5-23.5 38-41
5 22.5-23.5 22-23 23.5-24.5 41-44
6 22.5-24.5 22.5-23.5 24.5-25.5 44-46.5
7 24.5-26 23-24 23.5-26.5 46.5-50

Little Girls'

US Sizes Chest (in) Waist (in) Hips (in) Height (in)
4 21.5-22.5 21.5-22.5 33-35 38-41
5 22.5-23.5 22-23 23.5-24.5 41-44
6 23.5-24.5 22.5-23.5 24.5-25.5 44-46
6x 24.5-25 23-23.5 25.5-26 46.5-48.5

Chest: Place the tape measure under your arms at the fullest part of your chest, wrap around your body until your fingers meet and mark the measurement.
Waist: Measure around your natural waistline - right above your hips. Be careful not to squeeze too tight to allow a little give.